Title:
Educational device
United States Patent 3166856


Inventors:
Uttal, William R.
Application Number:
US17227562A
Publication Date:
01/26/1965
Filing Date:
02/09/1962
Assignee:
IBM
Primary Class:
Other Classes:
235/145R, 340/651, 400/74, 400/84, 400/666, 400/677, 400/715, 434/233
International Classes:
G09B13/00
View Patent Images:
US Patent References:
3103073Instructor system1963-09-10
3021937Selective interlock mechanism1962-02-20
2970386Arithmetic instructing aid circuit1961-02-07
2783454Data assembly apparatus1957-02-26
2613453Training typewriter1952-10-14
1984599Educational device1934-12-18
Foreign References:
DE153527C
GB762367A1956-11-28